Commit 1721632f authored by Li RongQing's avatar Li RongQing Committed by Luis Henriques

ipv4: fix a potential use after free in ip_tunnel_core.c

commit 1245dfc8 upstream.

pskb_may_pull() maybe change skb->data and make eth pointer oboslete,
so set eth after pskb_may_pull()

Fixes:3d7b46cd("ip_tunnel: push generic protocol handling to ip_tunnel module")
Cc: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: default avatarLi RongQing <roy.qing.li@gmail.com>
Acked-by: default avatarPravin B Shelar <pshelar@nicira.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
parent a591a8b6
...@@ -91,11 +91,12 @@ int iptunnel_pull_header(struct sk_buff *skb, int hdr_len, __be16 inner_proto) ...@@ -91,11 +91,12 @@ int iptunnel_pull_header(struct sk_buff *skb, int hdr_len, __be16 inner_proto)
skb_pull_rcsum(skb, hdr_len); skb_pull_rcsum(skb, hdr_len);
if (inner_proto == htons(ETH_P_TEB)) { if (inner_proto == htons(ETH_P_TEB)) {
struct ethhdr *eh = (struct ethhdr *)skb->data; struct ethhdr *eh;
if (unlikely(!pskb_may_pull(skb, ETH_HLEN))) if (unlikely(!pskb_may_pull(skb, ETH_HLEN)))
return -ENOMEM; return -ENOMEM;
eh = (struct ethhdr *)skb->data;
if (likely(ntohs(eh->h_proto) >= ETH_P_802_3_MIN)) if (likely(ntohs(eh->h_proto) >= ETH_P_802_3_MIN))
skb->protocol = eh->h_proto; skb->protocol = eh->h_proto;
else else
......
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